The present invention relates to a method and system for testing energy meters and similar instrumentation and, more particularly, to an energy testing method and system that is computerized and portable.
Energy meters are meters used to measure and record energy, such as electricity, which is produced, used or sold. These meters are typically subject to state regulation and, accordingly, must have their accuracy and calibration certified on a regular basis. Various test methods and equipment or systems have been used to certify energy meters. It is desirable, however, that these test methods and systems are capable of performing many tests, are portable, safe to use, and easily adaptable for future needs and changes in certification requirements.
The certification of energy meters can be performed in a calibration laboratory or at the site where the energy meter is normally operated. When calibration is performed in the laboratory, larger scale, automated, safe and accurate test equipment is readily available. For testing at the energy meter use site, on the other hand, many problems exist with presently available testing methods and systems.
Without the availability of automated test equipment, such as used in calibration laboratories, portable test systems require many testing operations be performed manually by the testing technician. These manual operations require removing the cover from the energy meters, often exposing service voltages as high as 480 volts, and require the use of extreme safety precautions. One such precaution is the use of insulating gloves to protect the technician from shock. These gloves, although necessary, are often stiff and clumsy, and limit the technician's finger movements making it difficult to operate switches and computer keyboards.
There are a number of different types of energy meters and, in many cases, different connections are needed to test these meters. Existing portable test systems do not provide to the test technician information pertaining to these connections. Existing portable test systems also do not perform all of the necessary tests requiring test technicians to carry around extra equipment.
While testing energy meters at their use site, existing portable test systems are powered from the service voltage at the site. The test voltages, currents, and phase angles therefore contain all of the amplitude variation, phase variation, noise and distortion existing in the service voltage source.
Furthermore, existing portable test systems are highly limited and inflexible for future changes in test requirements. These test systems cannot be customized to respond to changing requirements or changing equipment. Existing art and known developed equipment do not provide adequate capabilities for solving these and other associated problems with the testing of energy meters.